"Identify the molecule" league #18. Prize: knowledge + 100 STEM + 200 TMN

This contest is an attempt to promote scientific knowledge among community in a fun and interesting way with the help of molecules.
Some people like to travel around the world and tell others stories about what happens outside of our organisms/cells in other countries.
And with “Identify the molecule” contest you can try to travel inside our own organism/cells and cells of the organisms around us.

For more information about this contest read "Identify the molecule" contest. Upgrade (the league, additional bonuses and more) post.

Prizes/bonuses:

The prize here is

1. knowledge

facts, information, and skills acquired through experience or education; the theoretical or practical understanding of a subject
[Oxford Dictionary of English, 3rd Edition, Oxford University Press, 2010]

That understanding of our own organism and organisms around us is the real prize in the case of this contest. No matter what happens (whether or not you get 100 STEM), you can win (can acquire the knowledge by investigating different sources of information, remembering and using it to your advantage in the future).

2. 100 STEM

STEMGeeks is a community focused on STEM topics rewarding engagement with STEM tokens. STEMGeeks is powered by the Steem blockchain with it's own distribution model for STEM tokens in addition to the potential STEEM tokens.
STEM stands for Science, Technology, Engineering, Math and includes a wide range of science and technology topics.
[source]

3. 200 TMN

Aside from STEM I’d like to add TMN tokens.
For the uninitiated, TMN is the token of TranslateMe project (it’s about combining blockchain technology (NEO in this case) with translation industry).
The reason I’m going to add this token for the prize pool of this contest is not only because I have them, but because this contest is quite scientific, and TranslateMe project might help to solve the “lost” science problem.
For more on this you can read my post regarding TranslateMe (TranslateMe (or Decentralization meets Translation industry). Part 2. The “missing puzzle piece” of scientific ecosystem. General overview) (and other posts of that series (TranslateMe (or Decentralization meets Translation industry). Part 1. TranslateMe Chat App. Help to preserve languages, break language barriers, earn TMN. Twitter campaign (100 TMN bonus) and TranslateMe (or Decentralization meets Translation industry). Introduction)).

For more information on crypto-bonuses for this league, please refer to "Identify the molecule" contest. Upgrade (the league, additional bonuses and more) post.

Consider these tokens as a bonus.

Images and text are the clues for you to guess a riddle (the name of the molecule in this case).

Note that

a) even though this contest is called “Identify the molecule”,
-> molecule (singular)
sometimes it’s not just a molecule which is responsible for a specific function, but rather a complex of molecules.
Example:
cytochrome c oxidase (Complex IV)

is a large transmembrane protein complex… It is the last enzyme in the respiratory electron transport chain of cells located in the membrane.
source

b) some molecules/complexes have different names. For example, other names for cytochrome c oxidase (example above) are

Complex IV (mitochondrial electron transport).
Cytochrome a3.
Cytochrome aa3.
Cytochrome oxidase.
Warburg's respiratory enzyme.
source

Any of those names would be a valid entry.

c) Some almost identical molecules are grouped into classes / groups / families.
Example:
Helicases are divided into 6 groups. RecD and Dda molecules belong to helicases group (Superfamily 1 (SF1)). In this case you would need to guess only the name of the group –> Helicase/ Helicases.

d) Some proteins can have different forms – isoforms.
Example:
There’re trypsin 1 and trypsin 2. In this case you would need to guess only the general name – trypsin.

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Important

In order to get TMN, you’ll need to have NEO-wallet and provide me your public NEO-address.
If you don’t have it yet, don’t worry, I published a post on how/where to get it (O3 wallet).
Note that NEO-addresses provided by exchanges will not work in this case (+ it's safer NOT to keep your funds on exchanges). It's highly recommended to get O3 wallet.

If there’re no winners on any stage, the prize will be distributed equally among all users who provided any guesses for molecules.

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Riddle

The riddle here is about just one particular molecule, but it would be enough to name the group of the molecules to which it belongs.
Different types of this group of molecules are found among animal, microbial and plant kingdoms.
The molecule is the reasons why potatoes may taste sweet as you chew it.

(Surface representation. You can see the active site of the molecule highlighted in magenta & orange (aspartate (2 residues) & glutamate). The image was created by me with the help of PyMol - open source tool for molecular visualization/exploration. PDB-file was obtained from PDB)

The molecule was discovered more than 180 years ago.

It's important for beer brewing and breadmaking.

(Cartoon representation. You can see the active site of the molecule highlighted in magenta & orange at the center. The molecule requires Calcium to function (highlighted in red; chloride is highlighted in yellow. The image was created by me with the help of PyMol - open source tool for molecular isualization/exploration. PDB-file was obtained from PDB)

Some gene duplications of this molecule appeared after agricultural revolution (near 12,000 years ago).

The active site of the molecule in more details

(You can see the active site of the molecule highlighted in magenta & orange at the center. The molecule requires Calcium to function (highlighted in red; chloride is highlighted in yellow). The image was created by me with the help of PyMol - open source tool for molecular visualization/exploration. PDB-file was obtained from PDB)

"Edited"

Here’s the data showing where (in what human normal tissues) the gene of this molecule is expressed the most:

(in other words, those are the places where the molecule is present in abundance)

The data were obtained with the help of BioGPS

"Edited"

The molecule belongs to the group of enzymes called glycoside hydrolases/glycosidases/glycosyl hydrolases.

Rules

This contest lasts for 6 days.

Leave your guess (1 guess only) in the comments section of the post.

Don’t edit your comment and don’t provide any evidence that your answer is correct.

I’ll provide the answer in the comments section of the next post on the 7th day of the week’s stage.

The first user with correct answer is the winner.

Some of the clues have already been provided in the post.

Additional clues will be given in 2 days (on Monday, March 23, 2019, 20:00 ± 2 minutes UTC) (I’ll update this post).

And the rest of the clues will be provided in 2 more days (on Wednesday, March 25, 2019, 20:00 ± 2 minutes UTC) (I’ll update this post).

The reason is that some people might need less information to make conclusions that the others.

Additional clues will be added at the end of the "Riddle" section before the "Rules" section with "Edited" label.

The winner will be announced on Friday, March 27, 2019, 20:00 ± 2 minutes UTC in the comments section of the next post. Plus I’ll publish a detailed review of the riddle after a while.

I’ll transfer the tokens (STEM + TMN) (if the winner provides me his/her NEO-address) to the winner on that day (March 13) and add the transaction ID in the comments section.

I’m planning to run this contest every week.
So, you should expect to see the 2nd week’s riddle for January on Saturday, March 28, 2019, 20:00 ± 2 minutes UTC.

References

I’ll add all the references for this post later, because most of them contain the name of the molecule.
That would be a spoiler.
I’ll add them after a while.

Important

This contest is the work in progress.
A lot can be changed in the future.
Any recommendations/suggestions are very welcome.
If you have any questions, feel free to ask them in the comments section.

All images (without the license specified) are used under the doctrine known in USA as "Fair Use" (similar doctrines are used in other countries). For more information visit the US Gov website